Using fatty acid signatures to study bear foraging: Technical considerations and future applications

Abstract

Fatty acids (FA) ingested in the diet are incorporated into the adipose stores of predators in predictable ways. Consequently, the FA composition of the diet influences the FA composition of a consumer's adipose tissue. Over the last decade, this basic premise has been used to examine the foraging habits and trophic relationships of a variety of predators, including seals, whales, seabirds, and bears. By examining differences in the relative proportions of multiple FA (i.e., a FA signature), patterns of foraging can be detected across regions, over time, or among intraspecific groups. Development of FA signature analysis has reached the point where FA data from predators and prey can be incorporated into a statistical model that generates a quantitative estimate of predator diet. Here, I review how FA signature analysis has been applied to both qualitative and quantitative examinations of bear foraging. I discuss the techniques used to analyze and interpret FA data as well as some of the limitations of this approach. Finally, I suggest how this cost-effective technique can be further developed to provide an accurate picture of the ecological role of bears in a variety of habitats.